Canada’s main stock index fell on Monday as lower oil and metal prices weighed on energy and mining stocks, while Alimentation Couche-Tard Inc jumped after the convenience store operator bought a U.S. chain in an expansion move.

The energy group retreated 1.2 per cent, with oil prices falling as China ramped up exports of refined products, U.S. oil producers added rigs for an eighth straight week and prospects emerged for increased exports from Iraq and Nigeria.

Canadian Natural Resources fell 1.5 per cent to $41.15 and Suncor Energy Inc lost 0.7 per cent to $36.28.

The materials group, which includes precious and base metal miners and fertilizer companies, lost 1.2 per cent, as gold hit a two-week low and copper fell to its lowest in five weeks.

Barrick Gold Corp fell 1.4 per cent to $26.10 and Goldcorp Inc shed 1.9 per cent to $23.12, while diversified miner Teck Resources Ltd lost 1.7 per cent to $19.97.

At 11:45 a.m. EDT, the Toronto Stock Exchange’s S&P/TSX composite index was down 2.21 points, or 0.02 per cent, to 14,685.425.

Decliners were outnumbering gainers by around 3-to-1 and eight of the index’s 10 main groups were in negative territory, with consumer staples and health care sectors boosted by big moves in single stocks.

Couche-Tard jumped 6.8 per cent to $66.35 after the convenience store operator said it would buy U.S. chain CST Brands Inc in a roughly $4.4-billion deal.

Couche-Tard also said it would sell some Canadian CST assets to Parkland Fuel Corp, whose shares rose 12.1 per cent to $28.30.

Valeant Pharmaceuticals International Inc advanced 6.1 per cent to $39.21 after naming a new chief financial officer.

The financials group slipped 0.5 per cent, just ahead of the start of earnings season for the country’s biggest banks.

Industrials fell 0.4 per cent, while technology stocks lost 0.5 per cent.

Canadian wholesale trade increased by 0.7 per cent in June from May, the third consecutive monthly gain, Statistics Canada said.

Declining issues outnumbered advancing ones on the TSX by 179 to 57, for a 3.14-to-1 ratio on the downside.

The index was posting 4 new 52-week highs and 2 new lows.

The loonie fell against the U.S. dollar in late morning trading today as stock markets turned negative after a positive start.

The Canadian dollar was at 77.19 cents US, down 0.59 of a cent from Friday’s close.

With the earnings season coming to an end, investor focus will shift to Yellen’s speech on Friday at the annual central bankers’ meeting in Jackson Hole, Wyoming to see whether the Fed is keen on raising interest rates in the coming months.

The case for an imminent rate hike was strengthened by Fed Vice Chairman Stanley Fischer’s comments that the U.S. economy was close to hitting job and inflation targets.

Traders have priced in an 18 per cent chance of a rate hike for September, up from 12 per cent odds seen on Friday. That measure rose to 40.6 per cent for December from 39.1 per cent, according to the CME Group’s FedWatch tool.

Oil prices fell more than 2 per cent, retreating from last week’s two-month highs, on worries about burgeoning Chinese fuel exports, more Iraqi and Nigerian crude shipments and a rising U.S. oil rig count. [O/R] “This morning’s action is predicated on the perception of what’s going to happen in Jackson Hole as well with the weakness in oil prices which have had an impressive run in recent weeks,” said Andre Bakhos, managing director at Janlyn Capital LLC in Bernardsville, New Jersey.

Investor sentiment was earlier boosted by a couple of multi-billion dollar deals on Monday, including Pfizer’s $14-billion acquisition of cancer drug maker Medivation.